[Federal Register Volume 63, Number 16 (Monday, January 26, 1998)]
[Rules and Regulations]
[Pages 3654-3662]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-1783]



[[Page 3654]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket NHTSA-98-3342, Notice 1]
RIN 2127-AA43


Federal Motor Vehicle Safety Standards Rear Impact Guards; Rear 
Impact Protection

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation (DOT).

ACTION: Final rule; response to petitions for reconsideration; 
technical amendment; denial of petition to extend the effective date.

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SUMMARY: On January 24, 1996, NHTSA published a final rule establishing 
an equipment standard for underride guards and a vehicle standard which 
requires the installation of guards meeting the equipment standard on 
the rear end of heavy trailers and semitrailers. In response to 
petitions for reconsideration, NHTSA is amending that final rule to: 
clarify the 100 mm (4 inch) height requirement for the horizontal 
member of an underride guard, explicitly exclude from having to meet 
the energy absorption requirements all cargo tank motor vehicles 
manufactured with rear end protection complying with the high strength 
requirements of 49 CFR part 178 (to protect hazardous material) that 
occupies the area specified for NHTSA's underride guard, and increase 
the acceptable range of force application rates during testing. The 
agency is also excluding pulpwood trailers from the application of the 
vehicle standard and denying a petition from the Truck Trailer 
Manufacturer's Association (TTMA) for an extension of the effective 
date of the final rule.

DATES: The amendments made by this rule will become effective on 
January 26, 1998. Petitions for reconsideration of this rule must be 
received no later than March 12, 1998.

ADDRESSES: Any petitions for reconsideration should refer to the docket 
number and number of this notice and be submitted in writing to: 
Administrator, National Highway Traffic Safety Administration, Room 
5220, 400 Seventh Street, SW, Washington DC, 20590.

FOR FURTHER INFORMATION CONTACT: The following persons at the National 
Highway Traffic Safety Administration, 400 Seventh Street, SW, 
Washington, DC, 20590:
For non-legal issues:
    Dr. George Mouchahoir (Telephone: 202-366-4919) or Mr. Michael 
Huntley (202-366-0029), Office of Crashworthiness Standards
For legal issues:
    Mr. Paul Atelsek, Office of the Chief Counsel (202-366-2992), e-
mail: <a href="/cdn-cgi/l/email-protection#45352431202936202e052b2d3136246b212a316b222a33"><span class="__cf_email__" data-cfemail="f989988d9c958a9c92b997918d8a98d79d968dd79e968f">[email protected]</span></a>

SUPPLEMENTARY INFORMATION:

I. Background

    On January 24, 1996, the National Highway Traffic Safety 
Administration (NHTSA) published a final rule promulgating two new 
Federal Motor Vehicle Safety Standards (FMVSS) to require upgraded rear 
impact guards (underride guards) on trailers and semitrailers (61 FR 
2004).\1\ The first standard (No. 223, Rear impact guards) specifies 
performance requirements for strength and energy absorption for the 
underride guards themselves. This standard also contains a 
configuration requirement that the horizontal cross member of the guard 
be at least 100 mm (4 inches) high at any point across the guard width.
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    \1\ Although both trailers and semitrailers are equally affected 
by the rule, they will sometimes be referred to simply as 
``trailers'' in the remainder of this document.
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    As issued in January 1996, the standard requires testing the guards 
for strength by pushing with a 203 mm by 203 mm (8 inch by 8 inch) 
force plate at specified points along the horizontal member of the 
guard. The test continues displacing the force plate at a constant rate 
of between 1.0 and 1.5 mm/sec (0.04 and 0.06 inches/sec) in a forward 
direction, as the guard is oriented on the trailer, until the guard 
resists a specified force, or until 125 mm (5 inches) of displacement 
occurs. To pass, the guard has to resist the specified force within the 
first 125 mm (5 inches) of displacement.
    The standard's test for energy absorption is conducted by applying 
a force in the same way as in the test for strength, but only at one 
specified test point. The force is recorded at least ten times per 25 
mm (1 inch) of displacement until the 125 mm (5 inch) displacement is 
reached and the force plate is completely withdrawn from the guard. The 
guard energy absorption is calculated from a force vs. deflection 
diagram plotted using the recorded measurements. Only plastic 
deformation (permanent deformation) is counted toward meeting the 
required amount of energy absorption--elastic rebound of the guard does 
not count.
    The second standard (No. 224, Rear impact protection) requires most 
new trailers and semitrailers with a Gross Vehicle Weight Rating of at 
least 4,536 kg (10,000 pounds) to be equipped with a rear impact guard 
meeting the requirements of the equipment standard. This standard also 
specifies requirements for the location of the horizontal member of the 
guard relative to the rear end of the trailer or semitrailer, including 
a requirement that the rearmost surface of the member be located no 
more than 305 mm (12 inches) forward of the trailer's rear extremity. 
Certain types of trailers, including pole trailers and ``wheels-back'' 
vehicles, are excluded from the application of this rule.
    The January 1996 final rule on truck underride protection specified 
an effective date of January 26, 1998 and a March 11, 1996 deadline for 
receiving petitions for reconsideration on this rule.

II. Petitions for Reconsideration

    NHTSA received five petitions for reconsideration of the final rule 
from companies in the trailer and semitrailer equipment and 
manufacturing industries. In addition, one letter was received from an 
insurance group.
    The Insurance Institute for Highway Safety (IIHS) did not request 
any change to the rule. IIHS's letter sought to clarify what IIHS 
considered a misunderstanding (i.e., undercounting) on NHTSA's part 
regarding the potential number of lives saved as a result of the final 
rule. IIHS stated that this clarification was needed if the agency is 
to decide on future rulemaking actions on rear underride for single-
unit trucks or side underride for large trucks. NHTSA has met with IIHS 
staff to discuss their views on how best to estimate potential lives 
saved, and made adjustments in its data collection efforts to improve 
the quality of its data on underride crashes. The letter was not 
labeled as a petition and will not be addressed further.
    One of the petitioners was Rite-Hite Corporation which manufactures 
``dock locks,'' safety restraint equipment that is mounted on loading 
docks to secure trailers to the docks during loading and unloading. 
Rite-Hite requested that the agency modify the configuration and 
strength specifications of the guard to be compatible with its dock 
locks. It stated that the requirements of the final rule directly 
affect the ability of its dock locks to safely engage and hold trailers 
to the loading docks. The Rite-Hite loading dock device uses a hook 
that wraps around and over the rear protection guard to help prevent 
guards from riding up and over the restraining barriers, and to help 
prevent incidents

[[Page 3655]]

that can result from trailer tip-over and landing gear collapse. Rite-
Hite estimates that 100,000 of these dock locks currently exist.
    Rite-Hite asked NHTSA to comment on the role of its final rule with 
regard to limiting civil tort liability. Rite-Hite states that some 
vehicle manufacturers and others in the industry consider the final 
rule to be the sole factor to be considered in designing underride 
guards. It requested that the agency clarify that compliance with the 
final rule does not by itself insulate any manufacturer of rear impact 
guards from all civil tort liability. It also urged NHTSA to state that 
guard and trailer manufacturers must also take into account other 
safety issues, such as loading dock uses of rear impact guards, in 
making appropriate and reasonable design choices that are consistent 
with the final rule.
    Rite-Hite also petitioned for several changes to specific 
provisions of the final rule. It requested NHTSA to change the minimum 
cross sectional vertical height requirement in S5.1 of Standard No. 
223, which currently specifies that ``[t]he horizontal member of each 
guard shall have a cross sectional vertical height of at least 100 mm 
[4 inches] at any point across the guard width'' (emphasis added). Some 
manufacturers are manufacturing guards with horizontal members that are 
100 mm (4 inches) high on both the front and back sides of the 
horizontal member. Rite-Hite is concerned because the vehicle restraint 
may not engage properly in certain circumstances (e.g., abnormally high 
horizontal member, guard located forward of the rear extremity, poor 
alignment of the vehicle with the dock, and bumpers affixed to the 
horizontal member). It is also concerned that the restraint's warning 
light may not indicate the failure to engage without being modified.
    To address this potential problem, Rite-Hite petitioned NHTSA to 
either: (1) Specify 4 inches as the maximum height, (2) change the 
regulatory language to restrict the height specification to the rear-
facing side of the horizontal member, or (3) insert an interpretation 
that the existing language applies only to the rear-facing side of the 
horizontal member and an advisory that some vehicle restraint 
manufacturers recommend forward-facing surfaces be about 1.25 inches 
high.
    Rite-Hite also requested NHTSA to modify S5.2.1 of Standard No. 223 
to increase the minimum guard strength at location P2 (in the center of 
the guard, where Rite-Hite's dock locks attach). It stated that, 
because many vehicle restraints will provide 2-3 times more holding 
power than the guard strength requirement of the rule (50,000 N, or 
11,240 lb), guard strength is not sufficient to withstand the forces 
encountered during premature trailer pull-out from loading docks. 
Therefore, Rite-Hite petitioned the agency to increase the minimum 
force at test point P2 (where dock locks typically attach) to 
approximately 150,000 N (33,370 lb).
    Rite-Hite requested that the test procedures of S6.6 of Standard 
No. 223 be amended so the guard would have to meet similar strength 
requirements when pushed in a rearward direction (i.e., in the opposite 
direction from the striking vehicle) as it has to meet when it is 
pushed forward.
    Rite-Hite requested that NHTSA delete the exclusion from Standard 
No. 224 for ``wheels-back vehicles.'' These are vehicles on which the 
rear tires are fixed at a position within 305 mm (12 inches) of the 
rear extremity of the trailer. Rite-Hite suggested that there will be 
an increase of loading dock incidents without an underride guard to 
secure the rear of the trailer to the dock. It also argued that wheels-
back vehicles with wide-spaced single tires and no underride guard 
would increase the chance of passenger compartment intrusion, 
presumably by allowing the striking vehicle to penetrate between the 
tires.
    Rite-Hite also requested that the horizontal member of the guard, 
and of hydraulic guards in particular, not be permitted, as it 
currently is, to extend rearward of the rear extremity of the vehicle. 
The company is concerned about damage to the dock locks, the dock 
walls, the underride guard itself, and with the dock lock not properly 
engaging. It is also concerned that rear-extending guards will prevent 
the trailer from backing up flush with the dock, creating a gap between 
the trailer bed and the loading dock, even with a dock lock engaged. 
Rite-Hite states that this gap could cause loss of ``lip purchase'' of 
loading dock levelers on the bed of the trailer, and personal injury to 
loading dock employees. Rite-Hite also asked that NHTSA clarify that 
hydraulic guards must meet the dimensional and guard strength 
requirements for non-hydraulic guards.
    To ensure adequate engagement with dock locks, Rite-Hite also 
requested that the horizontal member be restricted to a position no 
more than 2 inches forward of the trailer rear extremity, rather than 
the currently permitted 305 mm (12 inches).
    Rite Hite wants the agency to specify a minimum horizontal guard 
member height of 457 (18 inches) above the ground. It is concerned that 
lower heights might not adequately engage the dock locks and might 
increase the chances of the guards being damaged by road surfaces and 
falling off.
    Finally, Rite Hite requested NHTSA to prohibit a sloped surface on 
the forward side of the rear impact guard and require a vertical 
surface there instead. Rite Hite states that the sloping surface will 
depress all kinds of vehicle restraints designed to hold on to the 
underride guard, thus causing disengagement.
    TTMA petitioned the agency to define ``cargo tank motor vehicle'' 
and make it clear that any vehicle so constructed would not have to 
meet the energy absorption requirements of the rule. It stated that the 
``present definition of a special purpose vehicle defines a cargo tank 
motor vehicle excluded by Standard No. 224 by its operational 
characteristics, namely, hazardous material held in transit, instead of 
by its construction characteristics.'' It noted that cargo tank motor 
vehicles are required by 49 CFR 178.345-8(d) <SUP>2</SUP> to have very 
strong rear end protection to protect the cargo tank and its piping in 
the event that another vehicle impacts it from the rear. TTMA argued 
that a manufacturer cannot design a guard to meet both the extreme 
rigidity requirements of 49 CFR 178.345-8(d) and the energy absorption 
(yielding) requirements of S5.2.2 of Standard No. 223.
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    \2\ These rules are administered by the Department of 
Transportation's Research and Special Programs Administration 
(RSPA).
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    Great Dane Trailers, Inc. (Great Dane) petitioned the agency to 
increase the permissible range of force application during the strength 
and energy absorption tests. It stated that the current requirement to 
maintain a constant rate of between 1 mm and 1.5 mm per second (60 mm 
and 90 mm per minute) ``may require expensive and sophisticated 
equipment'' and that the rate of displacement is not a significant 
indicator of the performance of the guard. Great Dane suggested 
changing the requirement to specify a rate that ``averages not less 
than 1 mm and not more than 25 mm per second over each 25 mm of 
displacement.''
    Great Dane also requested that the minimum energy absorption test 
be amended to double the displacement of the horizontal member of the 
guard. Great Dane stated that its current guards do not respond by 
plastic deformation until 75 mm (3 inches) of displacement has been 
achieved, and that stopping the test at 125 mm (5 inches) of 
displacement, as currently specified,

[[Page 3656]]

will require it to weaken the guards to meet the requirements. Great 
Dane petitioned to displace the guard to 250 mm (10 inches), thus 
ensuring more plastic deformation of the guards and increasing the 
energy absorption to 2-3 times the desired minimum. Great Dane 
subsequently forwarded test data that it believed supported its 
request.
    STRICK Corporation (STRICK), a trailer manufacturer, also expressed 
concern over the need to purchase expensive precision testing equipment 
to replace their current devices. In its testing, STRICK found it 
``impossible to determine the exact displacement for each and every 
second over the time of the test.'' STRICK petitioned to change the 
requirement from maintaining a constant rate of displacement between 1 
mm and 1.5 mm per second band to a requirement of ``displacement rate 
of the force is approximately constant over a time of 1 to 5 minutes''. 
STRICK is basically requesting a slower force application (i.e., more 
time, which would be required with a slower pump) to reach the 125 mm 
(5 inch) required displacement. STRICK also argued that the 
``displacement requirement'' in the final rule was inserted without 
adequate notice and represents a major change from the proposal.
    Finally, James King & Co. (King) petitioned the agency to amend the 
rule to require that rear truck underride guards protect from damage 
the reflective conspicuity markings required by Standard No. 108, 
Lamps, reflective devices, and associated equipment. King has observed 
that few manufacturers have provided the protective measures that NHTSA 
had suggested that manufacturers could take (e.g., mounting the 
reflective material in a steel channel or placing small metal beads 
above and below the reflective stripe). As a result, King believes 
that, contrary to the agency's assumptions, the majority of markings 
are damaged after a short time in use. King did not suggest a 
particular solution.

III. Response to Petitions

    NHTSA agrees with Rite Hite that mere compliance with NHTSA's 
vehicle safety standards does not insulate any guard or trailer 
manufacturer from civil liability. 49 U.S.C. 30103(e) explicitly states 
``[c]ompliance with a motor vehicle safety standard * * * does not 
exempt a person from liability at common law.'' NHTSA's standards are 
minimum standards that specify a floor, not a ceiling, for performance. 
They are intended to allow manufacturers flexibility in the selection 
of means of compliance. Designers of underride guards and trailer 
manufacturers that install them are free to consider the non-highway 
safety implications of their designs, including the functioning of the 
guards with existing dock locks.
    The agency also agrees with Rite Hite that the standard currently 
does not specify where, within its longitudinal cross section, the 
horizontal member of the guard must have a vertical height of 100 mm (4 
inches). Some guard manufacturers are apparently misinterpreting that 
provision as requiring a 100 mm (4 inch) height across the entire 
longitudinal cross section, from front to back.
    However, this reading is more design restrictive than the agency 
intended, and is not necessary for safety purposes. The 100 mm (4 inch) 
minimum height is intended to assure adequate engagement with and 
crushing of the frontal vehicle structure by preventing ``knife-
edging'' by a guard that is too thin. In the final rule, the agency 
concluded that this objective would be achieved by any guard with a 100 
mm (4 inch) cross sectional height that is forward of the rear 
extremity by not more than 305 mm (12 inches). The requirement in S5.1 
of Standard No. 223 for a cross sectional vertical height of 100 mm (4 
inches) does not need to be met in any specific transverse vertical 
plane. The important relationship is the distance between the trailer 
rear extremity and the forwardmost point at which at least 100 mm (4 
inches) of guard height would be engaged by a colliding vehicle.
    Given the preceding statement, Rite Hite's proposed changes to the 
regulation would unnecessarily restrict guard configuration. For 
example, it would be too design restrictive to require that the 100 mm 
(4 inch) cross section be measured at the rearmost point on the 
horizontal member, as Rite Hite suggests. This would be equivalent to 
saying that the guard must have a 100 mm (4 inch) vertical face at the 
rear. Although this design is common and probably the best at assuring 
immediate engagement, some manufacturers might prefer to use tubular 
designs for the horizontal member. Tubular designs would not comply 
with Rite Hite's suggested amendment, because the rearmost surface 
would be a line rather than a 100 mm (4 inch) high plane. Nevertheless, 
a tubular horizontal member would assure adequate engagement. It would 
also be too design restrictive to require that the cross section be 
vertical. Some shapes without vertical transverse cross sections of the 
required height might provide superior engagement or crash dynamics. 
For example, some guards might be shaped with sloped rear surfaces to 
account for the guard pivoting during a crash. As long as the 
horizontal projection of the horizontal member on a vertical plane 
presents a 4-inch high profile, then the desired objective will 
generally be achieved.
    The agency is concerned about the development of certain untested 
guard shapes, however. As previously stated, most current guard designs 
have a vertical face with a 100 mm (4 inch) minimum height at the first 
point of contact for an underriding vehicle. This configuration 
provided good protection for passenger vehicle occupants in the NHTSA's 
tests. The non-design-restrictive requirements should not imply 
encouragement of the development of horizontal members with convex 
cross sections at the rear. For example, some manufacturers might want 
to design guards with angular, or lens-shaped, cross sections to 
achieve better aerodynamic properties. The quality of engagement of 
such guard shapes with the underriding vehicle has not been evaluated.
    The agency is also concerned that portions of the horizontal member 
necessary for adequate engagement might be located more than 305 mm (12 
inches) forward of the vehicle's rear extremity. For example, on a 
guard with a 100 mm (4 inch) high tubular horizontal cross member whose 
rearmost surface is located the full 305 mm (12 inches) forward of the 
trailer rear extremity, a full engagement of the guard's horizontal 
member will not occur until it has advanced 305 mm (12 inches), plus 
the 25 mm (2-inch) radius of the tube. In some cases, engagement might 
come too late to prevent passenger compartment intrusion. The purpose 
of the requirement in S5.1.3 of Standard No. 224 regarding the location 
of the guard's rearmost surface is to assure that full engagement is 
achieved as early in the crash event as possible, but in any case 
before the passenger vehicle has penetrated more than 305 mm (12 
inches) under the trailer. Therefore, NHTSA is amending S5.1 to require 
that the vertical height requirement be met by the horizontally 
projected height of the horizontal member of the guard on a transverse 
vertical plane, and that the guard manufacturer's installation 
instructions or procedures specify that the forwardmost part of the 
horizontal member necessary to meet this requirement must be located no 
more than 305 mm (12 inches) forward of the rear extremity of the 
vehicle.
    The agency denies Rite-Hite's request to eliminate the wheels back 
vehicle exclusion in S3 of Standard No. 224, as it applies to the 
single-tire wheels back

[[Page 3657]]

trailers, because the agency does not have enough information on these 
vehicles at this time. However, NHTSA is concerned with the possibility 
that some smaller passenger vehicles could fit between the tires of 
these trailers. In this case, the passenger vehicle might advance past 
the rear extremity of the trailer by 305 mm (12 inches) before reaching 
the rearmost point on the rear tires, and then advance an additional 
distance approximately equivalent to the radius of these large tires, 
before contacting the axle. This distance, combined with the subsequent 
crush of the front end of the passenger vehicle, might allow passenger 
compartment intrusion. The agency appreciates Rite-Hite's concern about 
the lack of guards leading to an inability to engage dock locks. NHTSA 
notes that the rule does not prohibit ``partial'' guards in between the 
wheels of wheels back trailers. Manufacturers of excluded vehicles may 
install partial or full underride guards if they consider it essential 
to engage loading dock restraint devices.
    NHTSA requested data from TTMA on trailers and semitrailers with 
single rear tires. TTMA was able to confirm that these vehicles exist 
and provided a picture of one, but had no further information on hand. 
The agency also has little information on these vehicles, their tire-
to-tire spacing, or their uses. Therefore, NHTSA currently has 
insufficient information to determine whether the wheels back exclusion 
should continue to apply to these vehicles or whether partial guards 
might be appropriate. The agency is planning to begin collecting data 
within the National Automotive Sampling System starting in the summer 
of 1998 to define the scope of this potential problem. When NHTSA has 
gathered the appropriate information, it will consider whether a 
rulemaking is warranted to address the issue of single-tire wheels back 
vehicles.
    NHTSA denies the remainder of Rite-Hite's requests. These requests 
appear to be intended to ensure that guards are required to be 
compatible withRite-Hite's particular dock lock design. Although NHTSA 
is also interested in ensuring the safety of loading dock workers, the 
requested changes all tend to restrict underride guard design and 
reduce manufacturer flexibility that NHTSA considers essential to the 
practicability of the rule. Not all trailers and semitrailers use 
loading docks. Further, NHTSA understands that there are dock lock 
designs that do not require underride guard design restrictions. If 
trucking companies want maximum compatibility with all types of dock 
locks, including Rite-Hite's, there is nothing in NHTSA's rule to 
prevent them from ordering, or to prevent manufacturers from designing, 
underride guards exactly as Rite-Hite suggests.
    For the same reason that NHTSA is granting Rite-Hite's request to 
clarify that the cross-sectional vertical height requirement need not 
be met at the forward-facing surface of the horizontal member of the 
guard, the agency denies Rite-Hite's request to prohibit sloping 
surfaces or to require a maximum height of 1.25 inches on that surface. 
Because there are no vehicle safety benefits related to the shape and 
size of the forward-facing surface, it would be unnecessarily design 
restrictive to impose certain geometries or height requirements on that 
surface. Regardless of the geometry, Rite-Hite's petition indicates 
that manufacturers can adapt the forward-facing surface to be 
compatible with dock locks by attaching a \3/4\ inch metal bar to the 
bottom of the forward-facing surface. Standard No. 223 does not 
prohibit this approach.
    The agency also denies Rite-Hite's request to modify S5.2.1 of 
Standard No. 223 to require the guard's strength at location P2 be 
increased to approximately 150,000 N (33,370 lb). A guard strong enough 
to withstand the forces encountered when drivers attempt to pull out 
while still locked to the dock is not necessary for crashworthiness. 
This request pertains to the strength of the guard in the opposite 
direction (i.e., rearward) from the one specified in the final rule. 
The rule specifies a minimum strength to withstand forces in the 
forward direction, such as would result from an underriding vehicle. 
The rule does not regulate the requested aspect of performance, and 
regulating it would not serve the purpose of the rule. For the same 
reasons, the agency denies Rite-Hite's request that S6.6 of Standard 
No. 223 be amended so there is a rearward direction force application 
test in addition to the specified forward direction test. NHTSA again 
notes that there is nothing in the rule to prevent guard manufacturers 
from designing guards as Rite-Hite suggests, with 150,000 N (33,370 lb) 
strength in the rearward direction.
    The agency denies Rite-Hite's request to amend the language of 
S5.1.3 of Standard No. 224 to prohibit the horizontal member of the 
guard from extending rearward of the transverse vertical plane tangent 
to the rear extremity of the vehicle. NHTSA expects that manufacturers 
will not design, and trucking companies will not order, underride 
guards for uses that will damage loading docks, dock locks, loading 
dock levelers, and the guards themselves. NHTSA is aware of some 
trailer and semitrailer applications for which a guard extending 
rearward of the trailer rear extremity is useful. These applications do 
not use loading docks. In addition, rearward mounting is useful in 
preventing underride and passenger compartment intrusion by the rear of 
the passenger vehicle. The agency does not want to prohibit these 
benefits for the sake of regulating the unlikely occurrence of 
excessively rearward guard location. For the same reasons, Rite-Hite's 
request that ``hydraulic guards not hinge rearward of the transverse 
vertical plane tangent to the rear extremity of the vehicle'' is 
denied. NHTSA notes that hydraulic guards are already required to meet 
the same dimensional and strength requirements as non-hydraulic guards.
    NHTSA denies Rite-Hite's request to prohibit positioning the guard 
more than 2 inches forward of the trailer rear extremity. This would 
eliminate nearly all of the fore-aft flexibility that the agency 
believes that manufacturers need in positioning their guards, merely 
because a distance more than 50 mm (2 inches) will not be compatible 
with Rite-Hite's restraint. NHTSA emphasizes that the final rule 
specified mounting the guard within a range of 305 mm (12 inches) or 
less, and as close to the rear extremity as practical. This requirement 
is probably sufficient to ensure that the vast majority of trailers and 
semitrailers are compatible with Rite-Hite's needs. Nearly all guards 
are currently being mounted flush with the trailer rear extremity. 
NHTSA does not believe that the final rule will change that practice. 
If a certain kind of guard is needed for safely docking with dock 
locks, trucking companies will presumably specify such guards in their 
orders for new vehicles. This would be an additional factor making 
change unlikely.
    NHTSA denies Rite-Hite's request that S5.1.2 of Standard No. 224 be 
amended to prohibit mounting guards with the horizontal member lower 
than 457 mm (18 inches) from the ground. The possibility of guard 
damage, along with the extensive comments received from the public on 
ground clearance, were discussed at length in the preamble of the 
January 1996 final rule. The comments indicated that it would be 
impractical to mount the guards much lower than the maximum clearance 
of 560 mm (22 inches) anyway. The agency does not expect vehicle 
manufacturers to mount guards at heights at which the guards or the 
vehicles would be damaged due to operational restrictions (e.g., 
railroad crossings). In addition,

[[Page 3658]]

higher costs of lower guards and the difficulty of meeting the strength 
requirements at lower heights are additional factors that will keep 
most manufacturers from producing guards that are lower than the 
maximum height. Therefore, setting a minimum clearance requirement is 
unnecessary. Assuming manufacturers did want to produce them for uses 
with fewer operational restrictions, lower guards would be safer in a 
crash. NHTSA has no evidence that loose guards are falling off and 
creating a highway hazard. Regulation is not necessary in this area.
    The agency agrees with TTMA that the current language of Standard 
No. 224's definition of ``special purpose vehicle'' might be 
interpreted to exclude cargo tank motor vehicles due to their 
operational use, rather than their construction characteristics. The 
rule defines special purpose vehicles as having ``work-performing 
equipment (including any pipe equipment that would hold hazardous 
materials in transit * * *) that, while the vehicle is in transit, 
resides in or moves through the area that could be occupied by the 
horizontal member of the rear impact guard * * *'' The phrase ``that 
would hold hazardous materials'' might, in the case of a cargo tank 
motor vehicle, imply that the exclusion depends on the intentions or 
subsequent actions of the purchaser of the cargo tank motor vehicle. 
Although manufacturers generally know that trailer owners willing to 
pay for a trailer certified to RSPA's standards are planning to 
transport hazardous materials, the manufacturer of a cargo tank motor 
vehicle should not be charged with the responsibility for determining 
what its use will be after it is out of the manufacturer's control.
    Therefore, as the TTMA requested, the agency is deleting the phrase 
in the definition of special purpose vehicle that explicitly recognized 
pipe equipment that would carry hazardous material as work performing 
equipment. Piping that carries hazardous materials would still be 
considered work-performing equipment, as would any other piping that 
needs to occupy the area of the guard while the vehicle is in transit. 
However, piping carrying hazardous materials would probably not be 
located in such an exposed location, because RSPA's regulations (e.g., 
178.345-8, 178.338-10) generally require that such piping be protected 
by RSPA's vehicle rear end protection device or rear 
bumper.<SUP>3</SUP>
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    \3\ Both terms are used to refer to underride guard-type devices 
in RSPA's regulation. ``Rear-end protection device'' is used in 49 
CFR 178.345, while ``rear bumper'' is used in 49 CFR 178.337 and 
178.338. These terms are used below when discussing cargo tank motor 
vehicles, both to avoid confusion and to emphasize the different 
primary purpose they serve--protecting hazardous material in the 
tank, rather than protecting colliding vehicle occupants with crash 
protection.
---------------------------------------------------------------------------

    The standard still needs to be revised to prevent conflict with 
RSPA's rule. The high strength requirements for cargo tank motor 
vehicle rear end protection devices or rear bumpers in RSPA's 
regulations are incompatible with NHTSA's energy absorption 
requirement. NHTSA intended to apply only the configuration and 
strength requirements, but not the energy absorption requirements, to 
vehicles meeting RSPA's requirements with rear-end protection device or 
rear bumpers in the area specified by NHTSA for the underride guard. 
NHTSA's strength requirements are far lower than RSPA's, so meeting 
NHTSA's strength requirements will not be a problem for hazardous 
materials cargo tank motor vehicles. The agency stated in the final 
rule (at 61 FR 2023) that:

    RSPA's rule for underride guards on hazardous materials tankers 
(49 CFR Part 178.345-8) is generally compatible with this rule, and 
this rule applies to hazardous materials tankers. However, to 
prevent any confusion as to the relationship between RSPA's rule and 
NHTSA's rule, this rule explicitly recognizes that piping that 
carries hazardous materials while in transit needs the special 
protection that is provided by RSPA's rule.

    Explicitly recognizing vehicles with the pipe equipment in the area 
of the guard as special purpose vehicles did not capture within the 
exclusion all the vehicles that must be excluded. Any tanker built to 
conform to RSPA's regulations with a rear-end protection device or rear 
bumper in the area specified for NHTSA's underride guard cannot 
practically comply with NHTSA's energy absorption requirement, 
regardless of whether it has pipe equipment in the area of the guard or 
whether the pipe equipment passes through the area where the guard 
could be located.
    Therefore, NHTSA is adding a paragraph to the Application section 
of Standard No. 224 explicitly excluding all cargo tank motor vehicles 
built to RSPA's standards, including insulated cargo tanks and tanks 
that carry compressed gases, from the requirement to meet the energy 
absorption requirements of S5.2.2 of Standard No. 223, if the rear-end 
protection device or rear bumper is in the area specified for NHTSA's 
underride guard.
    The agency is stating the exclusion more broadly than the TTMA 
suggested. The TTMA petitioned to add a definition for a cargo tank 
motor vehicle, which referenced some (but not all) of RSPA's tanker 
specifications. In NHTSA's view, the benefits of energy absorption for 
the striking vehicle are outweighed by the additional danger to that 
and other vehicles from spillage of hazardous cargo, so that all 
tankers that might be carrying hazardous materials should be excluded 
from the energy absorption requirement. RSPA occasionally adds cargo 
tank motor vehicle specifications and may also add vehicle rear end 
protection device or rear bumper specifications to its regulations. If 
the rule referenced RSPA's regulations for every specific tanker and 
guard type, every change to the RSPA regulations would necessitate a 
corresponding change to Standard No. 224's application section. Due to 
the difficulty of coordinating interagency rulemakings and effective 
dates, the rule simply references the part of RSPA's regulations that 
specifies cargo tank motor vehicles and rear end protection devices or 
rear bumper requirements, and excludes from the energy absorption 
requirements of this rule all cargo tank motor vehicles that comply 
with that part and have a rear end protection device or rear bumper in 
the area specified for the underride guard. Any future changes by RSPA 
to its tanker guard requirements will likely be made to this part, and 
would be automatically incorporated by reference in Standard No 224.
    The agency notes that this exclusion from the energy absorption 
requirements for RSPA guards on cargo tank motor vehicles applies only 
when the RSPA rear end protection device or rear bumper occupies the 
space specified for the horizontal member of the NHTSA guard and meets 
the configuration and strength requirements specified for the NHTSA 
guard. For example, many cargo tank motor vehicles have a rear end 
protection device or rear bumper located several feet off the ground. 
The guards on these trailers are not excluded from NHTSA's energy 
absorption requirement of Standard No. 223.
    The requests of Great Dane Trailers and STRICK Corporation 
regarding the rate of force application in the tests for strength and 
energy absorption can be treated together. NHTSA agrees that changing 
the displacement rate requirements in S6.6(a) of Standard No. 223 to 
accommodate concerns about the practicability of the test procedure 
would not affect the intent of the rule or the determination of the 
guard's strength. The objective of the requirement is to assure that 
the guard

[[Page 3659]]

is being tested quasi-statically because the specified test procedure 
is not a dynamic test.
    The specified rate of displacement during force application (1.0 to 
1.5 mm/s) may be narrow and too restrictive to accommodate slow-pumping 
force application equipment. NHTSA accepts Great Dane's and STRICK's 
assertions that new and expensive equipment would be required for those 
companies to achieve this rate. More powerful hydraulic pumps are 
required to achieve higher rates of displacement during the test, 
especially with stronger guards. The agency has no information on how 
powerful STRICK's pumps are, but NHTSA chose the quasi-static test 
procedure at least in part to accommodate small trailer manufacturers 
that presumably have less sophisticated equipment. For steel, the most 
common guard material, the rate of force application, within reasonable 
bounds, should not make a significant difference in the test results.
    For reasons that seem inconsistent with the basis for their 
requests, both companies asked for an increase in the permitted 
displacement rate. The agency denies these requests. Great Dane 
requested an increase in the upper limit of the specified range from 
1.5 mm/sec to 25 mm/sec, and STRICK requested an increase to 2.08 mm/
sec. At a displacement rate of 25 mm/sec, a 125 mm (5-inch) test 
displacement would be completed in a very short duration of about 5 
seconds. This is a very fast force application and conflicts with the 
intent of the rule to specify a quasi-static, not a dynamic, test 
procedure. Moreover, Great Dane's proposed rate of 25 mm/s would 
require high precision and sophisticated computer-controlled test 
equipment as well as powerful and efficient pumps--potentially 
representing upgraded equipment that both companies state they want to 
avoid. The agency notes that NHTSA's Vehicle Research and Test Center 
(VRTC) successfully performed its testing program for the subject final 
rule using manually-controlled test equipment with no special 
instrumentation. Less sophisticated equipment with lower pump capacity 
requires more, not less, test duration. The current upper limit on the 
rate of displacement during force application of 1.5 mm/sec is being 
retained. This should not present a problem for Great Dane or STRICK, 
because lower displacement rates can also be selected on more capable 
equipment.
    Regarding the lower bound for displacement rate, the agency 
believes that 6.3 minutes is adequate time to achieve the required 
displacement without the need for sophisticated control equipment and 
powerful pumps. No petitioner has requested a longer period and, unless 
the agency is presented with evidence of a problem with this rate, it 
will consider longer periods as unnecessarily prolonging certification 
and compliance testing. As explained earlier, reasonably slower 
displacement rates will probably not make a significant difference in 
test results anyway. Therefore, NHTSA is granting part of STRICK's 
request and widening the specified displacement rate range to allow 
displacement rates as low as 0.33 mm/sec. Testing at this rate will 
allow a 125 mm (5 inch) test displacement to be achieved in a period of 
about six minutes.
    The range of force displacement rate will now be specified in 
centimeters and minutes rather than in millimeters and seconds, i.e., 
as 2.0 cm/minute to 9.0 cm/minute. This range replaces the currently 
specified range of 1.0 to 1.5 mm/sec (6.0 to 9.0 cm/minute). The larger 
distance per time period is easier for most people to visualize. It is 
NHTSA's understanding that the displacement rate on most modern test 
equipment (and on all the equipment NHTSA would use for compliance 
testing) is controlled by a computer with a feedback system capable of 
quickly and automatically adjusting the displacement rate. However, for 
purposes of certification testing on non-computer controlled equipment, 
precise adjustment is impractical. Specifying the distance on a per-
minute time scale will allow for practical adjustments of the rate of 
displacement within each minute. This change would result in a more 
practical test procedure and should not compromise the performance 
requirements of the rule. The language of section 6.6(a) of Standard 
No. 223 is changed accordingly.
    The word ``constant'' has been eliminated from the test procedure 
as a modifier of the displacement rate. As Great Dane pointed out, the 
term ``constant'' is confusing because it is so absolute. The concept 
of tolerance, for purposes of compliance testing, has been introduced 
as explained below.
    Normally, when NHTSA specifies a range in the test conditions of 
its standards, the equipment being tested is expected to meet the 
specified performance requirements when testing at any point within the 
range. In this case, the agency is allowing a broader range of 
displacement rates (with a significantly slower rate of displacement at 
the lower end of the range) than was allowed originally, to accommodate 
the manufacturers' desire to conduct certification testing with their 
existing equipment. Applying the usual procedure, NHTSA could test and 
expect compliance at any rate within the wider displacement rate range. 
However, this would have the effect of making it more, not less, 
difficult for manufacturers to certify compliance, because the same 
requirements would have to be met under a wider range of conditions. 
The agency notes again that tests within the new range of displacement 
rates should yield similar results to tests within the old range 
because the performance of most current guard materials is not rate 
sensitive even over this broader range of load application rates.
    Because merely granting the petitioner's request would not achieve 
the petitioner's objective of making certification testing easier, 
NHTSA will allow the guard manufacturer to designate the displacement 
rate, within the range of 2.0 to 9.0 cm/minute, on which it based its 
certification. If compliance tests are conducted by the agency, the 
manufacturer's designated rate, plus or minus 10 percent, will be used. 
The practical effect of this is that the guard must comply at the 
designated rate as well as any rate within 10 percent above or below 
that rate. As noted above, having to maintain a ``constant'' designated 
displacement rate would make it practically impossible for the agency 
to conduct compliance testing. For the same reason, NHTSA will not 
attempt to duplicate during compliance testing the deflection/time 
curve that the manufacturer experienced during certification testing. 
As long as the agency stays within the 10 percent tolerance during the 
entire test, the compliance test will be valid. If the manufacturer, 
for whatever reason, does not designate a displacement rate, NHTSA may 
pick any rate within the specified range.
    NHTSA denies Great Dane's request to amend the energy requirement 
to require twice as much displacement for the purpose of the energy 
absorption test. The petitioner stated that the ``current limit of 125 
mm will require guards which are weaker (less stiffness) be installed 
merely to meet the energy absorption level of 5650 J.'' This amendment 
would have the effect of allowing stiffer guards by displacing the 
guard 250 mm (10 inches) instead of 125 mm (5 inches) before measuring 
to determine whether the guard absorbed the minimum 5,650 joules (4,170 
ft-lbs) of energy. The greater displacement would make it easier for 
the required plastic deformation of the guard to occur. However, the 
point of the energy absorption requirement is to prevent

[[Page 3660]]

overly stiff guards. It would enhance crash safety if manufacturers 
weaken guards that are too stiff, because this will allow a softer 
``crash pulse'' for the colliding passenger vehicle by ``riding down'' 
the speed over a short distance during the crash.
    Moreover, NHTSA notes that the data that Great Dane submitted in 
support of this request does not indicate that any change is needed in 
the standard. The test data provided by Great Dane show that the guards 
they tested displayed more than twice the required energy absorption 
when tested according to the current requirement of 125 mm (5 inches) 
of displacement.
    Finally, the agency denies King's request to amend the final rule 
to include requirements that rear underride guards protect conspicuity 
markings from damage. The Federal Highway Administration (FHWA) has 
jurisdiction over trailers after the first sale for purposes other than 
resale and regulates the maintenance of required safety equipment. 
Section 393.11 of the Federal Motor Carrier Safety Regulations (FMCSRs) 
requires that commercial motor vehicles meet the requirements of 
Standard No. 108 in effect at the time the vehicle was manufactured (49 
CFR 393.11). Since December 1, 1993, Standard No. 108 has required new 
trailers to meet conspicuity requirements. Accordingly, motor carriers 
are currently required under FHWA regulations to maintain the 
conspicuity treatments on these trailers. This includes maintaining the 
conspicuity treatment on the horizontal member of the underride guard.
    On April 14, 1997, FHWA issued an NPRM (62 FR 18170) that would 
amend the FMCSRs at 49 CFR 393.11, Lighting Devices and Reflectors, to 
make certain that all motor carriers operating trailers subject to the 
FMCSRs are aware of their responsibility to maintain the conspicuity 
treatments in all locations required by Standard No. 108. However, FHWA 
requested comment on whether an exemption from the maintenance 
requirement for the tape on the underride guard should be provided due 
to practicability problems.<SUP>4</SUP> NHTSA has forwarded King's 
comment to FHWA for consideration. Irrespective of whether FHWA 
continues to require motor carriers to maintain the conspicuity 
treatment on the guards, NHTSA encourages manufacturers to design the 
treatment to be as durable as practicable to ensure that the safety 
benefits of applying the treatment to that location are realized.
---------------------------------------------------------------------------

    \4\ ``The [FHWA Notice of Proposed Rulemaking] does not, 
however, include an exemption to the requirement that motor carriers 
maintain the conspicuity material on the rear underride device. The 
agency requests comments from motor carriers on the durability of 
the conspicuity material located on the horizontal member of the 
rear underride protection devices. Commenters are asked to identify 
the specific types of trailers and operating conditions that they 
believe are associated with the durability problems cited in 
addition to providing color photographs of the damaged conspicuity 
materials.'' 62 FR 18172-73.
---------------------------------------------------------------------------

    If FHWA requires the conspicuity treatment on the horizontal member 
of the guard to be maintained, and sufficiently durable conspicuity 
treatments are not available, NHTSA assumes that manufacturers would 
design guards with channels or other protective features for the 
conspicuity treatment. There is nothing in Standard No. 223 that would 
prevent such designs. NHTSA will consult with FHWA on whether NHTSA 
rulemaking to mandate physical protection for conspicuity treatment is 
needed after FHWA completes its rulemaking.

IV. Response to TTMA Petition on Extension of Effective Date

    In an April 18, 1997 letter, TTMA petitioned NHTSA to commence 
rulemaking to extend the effective date from January 26, 1998 to a date 
at least nine months after this response to the petitions for 
reconsideration is issued. It stated only that trailer manufacturers 
were reluctant to complete the designs of their guards and test these 
guards until the petitions were answered.
    TTMA's petition for an extension of the effective date is denied. 
NHTSA does not see any reason why manufacturers can not complete and 
test their guard designs in the allotted time. Except for a few of Rite 
Hite's requests, all the petitions dealt with relatively minor issues 
of testing and clarification. Manufacturers should have been planning 
to comply with the rule as it was published in January of 1996.
    The guards that will be required on January 26, 1998 are very 
similar to guards currently being produced. NHTSA made no amendments 
requiring configuration changes in its responses to the petitions. The 
change to the regulatory text relating to vertical cross-sectional 
height is basically a clarification of the current requirements. There 
were only two minor changes to the test procedures (allowing a more 
flexible force application rate and allowing the manufacturer to 
designate the force application rate on which it based its 
certification). These changes will make it easier for manufacturers to 
test the guards and to comply with the requirements. The guards that 
manufacturers will be required to produce after this rule is issued 
will be essentially the same guards that NHTSA required in the January 
1996 final rule. NHTSA notes that the TTMA's Recommended Practice, 
``Rear Impact Guard and Protection'' is virtually identical to the 
NPRM, except for the energy absorption requirement of Standard No. 223. 
This Recommended Practice is designated RP No. 92-94, and was 
originally issued in April of 1994 and revised in November of 1994. 
Apparently it has been adopted as an industry standard, so little 
reengineering should be necessary to meet Standard No. 223. Therefore, 
NHTSA believes that the manufacturers have had sufficient time to 
complete their designs prior to the January 26, 1998 effective date. A 
general extension is not warranted.
    However, the agency will consider petitions for temporary exemption 
from Standard No. 224. The agency has received a number of these 
petitions from small-volume trailer manufacturers within the past few 
months. Under 49 CFR 555.6(a), a manufacturer whose yearly production 
is not more than 10,000 units may ask for a temporary exemption from a 
Federal motor vehicle safety standard for up to three years on the 
basis that compliance would cause it substantial economic hardship and 
that it has attempted in good faith to comply with the standard from 
which it has asked to be excused. Part 555 requires the agency to 
publish a notice in the Federal Register seeking public comment on each 
exemption petition before a decision can be made on such a request, and 
then publish a second notice either granting or denying the petition. 
NHTSA expects to issue final decisions on these petitions approximately 
three to four months after the date of submission of the petition.

V. Technical Amendment on Logging Trailers

    The Application section (S3) of Standard No. 224 currently excludes 
``pole trailers'' from the application of the rule. Pole trailers are 
trailers with a single, longitudinal telescoping pole, rather than a 
normal trailer chassis, connecting the front wheels to the back wheels. 
Pole trailers are predominantly used by the logging industry to 
transport logs. They spend a great deal of their time off-road at 
logging sites and on rough logging roads. NHTSA proposed to exclude 
these vehicles in the January 8, 1981 NPRM (46 FR 2139), stating:

the proposed rule does not apply to pole trailers. The agency 
believes that requiring underride guards on such vehicles would 
provide little benefit to car occupants. Since the poles carried by 
these trailers normally overhang the back end of the vehicles for a 
considerable distance, the danger of

[[Page 3661]]

underride is due not to the structure of the trailer but to the 
structure of the cargo.

This was not a controversial exclusion and it was retained in the 1992 
Supplemental Notice of Proposed Rulemaking (SNPRM) and the 1996 final 
rule without comment.

    Changes in the trailer design and in the logging industry since 
1981 have led to a decline in the popularity of pole trailers and the 
emergence of ``pulpwood trailers'' to take their place. Pulpwood 
trailers are similar in use and structure to pole trailers, but they 
have more structure (often two poles or beams) connecting the front 
wheels to the back wheels. NHTSA has recently become aware, through an 
April 25, 1997 letter from Mr. Buck Ford, that some manufacturers of 
pulpwood trailers are deciding how to install underride guards to 
comply with the January 1996 final rule, but that other manufacturers 
are completely unaware of the rule. Pulpwood trailers are not currently 
excluded because they are not technically pole trailers. According to 
Mr. Ford, there may be a shortage of pulpwood trailers in 1998 due to 
few manufacturers being able to meet the requirements.
    NHTSA intended to exclude all trailers that, like pole trailers, 
lack structure for attaching guards and that would carry loads likely 
to overhang the rear of the trailer substantially when it published the 
January 1996 final rule. Pulpwood trailers do not differ significantly 
from pole trailers in their construction or use. They also carry 
overhanging logs that would negate the value of the underride guard and 
operate on rough logging roads on which an underride guard would be a 
serious impediment. Due to the lack of controversy regarding the 
exclusion of pole trailers, and due to the lack of comment from 
pulpwood trailer manufacturers, the agency assumed that the language of 
the exclusion covered all trailers of this type.
    Because this appears to have been an incorrect assumption, NHTSA is 
adding pulpwood trailers to the list of excluded vehicle types. This is 
being done by technical amendment because the agency's intent to 
exclude vehicles that carry this kind of load was clear from the 1981 
NPRM's rationale for the exclusion. This technical amendment will also 
avoid a shortage of pulpwood trailers needed by the logging industry in 
1998. NHTSA is adopting the pertinent part of the language contained in 
Standard No. 121, Air Brake Systems, which defines ``pulpwood trailer'' 
as ``a trailer that is designed exclusively for harvesting logs or 
pulpwood and constructed with a skeletal frame with no means for 
attachment of a solid bed, body, or container * * *''.

VI. Effective Date

    The agency finds that there is good cause to make this rule 
effective immediately. These amendments do not impose any new 
requirements. Instead, they relieve some of the testing burden imposed 
on the manufacturers by the January 24, 1996 final rule. It will be 
slightly easier for manufacturers to test using the new load 
application rates specified in these amendments. These amendments also 
make it clear that pulpwood trailers are an excluded category of 
vehicle, and that cargo tank motor vehicles built to RSPA's standards 
with a rear-end protection device or rear bumper in the area specified 
for NHTSA's underride guard do not have to meet the energy absorption 
requirements of Standard No. 223. A delayed effective date would impose 
a needless compliance burden on the trailer industry, including many 
small businesses that manufacture trailers.

VII. Rulemaking Analyses and Notices

A. Executive Order 12866 (Federal Regulation) and Regulatory Policies 
and Procedures

    This rulemaking action was reviewed under Executive Order 12866. 
The action has been determined to be ``not significant'' under 
Executive Order 12866 and under the Department of Transportation 
regulatory policies and procedures. The Final Regulatory Evaluation 
(FRE) for the January 1996 final rule describes the economic and other 
effects of that rule in detail.
    The responses to these petitions for reconsideration and this 
technical amendment do not alter the costs or benefits of that rule 
significantly. They merely clarify the intended application of the rule 
and provide more flexibility in the test procedures. They do not change 
the requirements enough to significantly alter the performance or the 
price of rear underride guards. Therefore, a regulatory analysis is not 
warranted.

B. Regulatory Flexibility Act

    NHTSA analyzed the potential impacts of the January 1996 final rule 
on small entities under the Regulatory Flexibility Act and certified 
that it would have a significant economic impact on a substantial 
number of small entities. NHTSA has described those possible impacts in 
the FRE to the January 1996 final rule, which was, in part, a 
regulatory flexibility analysis.
    The responses to these petitions for reconsideration and this 
technical amendment slightly increase manufacturer flexibility in 
testing, but NHTSA certifies that the changes made by today's rule do 
not have a significant economic impact on a substantial number of small 
entities. Most of the changes are interpretations and clarifications of 
the existing language, not changes in requirements that impose new 
burdens. The changes in requirements are designed to make the guards 
easier for manufacturers, especially small businesses, to test their 
guards, not to change the guard performance. As a result, some 
businesses that otherwise would have had to buy sophisticated testing 
equipment or change their guard designs unnecessarily will not need to 
do so. Therefore, there will be no new significant impact on small 
businesses.

C. Executive Order 12612 (Federalism)

    NHTSA has analyzed this rule in accordance with the principles and 
criteria contained in E.O. 12612, and has determined that this rule 
will not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    This rule makes only minor changes to the January 1996 final rule 
which had only minimal federalism implications. Nearly all States 
require underride protection guards for heavy trailers and 
semitrailers. Further, most states require that the guards meet certain 
configuration requirements, or that they be positioned in a certain 
location relative to the rear and sides of the vehicle. The January 
1996 final rule will preempt State requirements for rear impact 
protection. However, the agency believes that federalism implications 
will be minor because the guards required by that final rule are not 
fundamentally different from those required by State law. Several 
States, including Michigan, North Carolina, New York, and New Jersey, 
already require trailers longer than 15 m (50 ft) to have guards with 
the configuration required by that rule. For practical purposes, the 
only effect that that rule will have in these States is to require the 
guards to be tested and certified for strength and energy absorption.
    NHTSA believes that effective rear impact protection measures can 
be implemented only at the national level. Only vehicle manufacturers 
can produce trailers and semitrailers with improved rear impact 
protection. The improvements required by the January 1996 final rule 
will cause vehicle manufacturers and operators to incur costs that 
could affect their competitive

[[Page 3662]]

position if compliance were voluntary and attempted by some, but not 
all manufacturers. That rule applies uniformly to all manufacturers and 
will ensure that the competitive position of the manufacturers will not 
be significantly affected by the required safety improvements.

D. Preemptive Effect and Judicial Review

    Under 49 U.S.C. Sec. 30103(b), whenever a Federal motor vehicle 
safety standard is in effect, a State may not adopt or maintain a 
safety standard applicable to the same aspect of performance which is 
not identical to the Federal standard. 49 U.S.C. Sec. 30161 sets forth 
a procedure for judicial review of final rulemaking establishing, 
amending, or revoking Federal motor vehicle safety standards. That 
section does not require submission of a petition for reconsideration 
or other administrative proceeding before parties may file suit in 
court. This final rule does not have any retroactive effect.

E. Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1980 (P.L. 96-
511), there are no new requirements for information collection 
associated with this response to petitions for reconsideration and 
technical amendment.

List of Subjects in 49 CFR Part 571

    Imports, Incorporation by reference, Motor vehicle safety, Motor 
vehicles, Rubber and rubber products, Tires.

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

    In consideration of the foregoing, 49 CFR part 571 is amended as 
follows:
    1. The authority citation for part 571 continues to read as 
follows:

    Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166; 
delegation of authority at 49 CFR 1.50

    2. Sections S5.1 and S6.6(a) of 49 CFR 571.223 are revised to read 
as follows:


Sec. 571.223  Standard No. 223; rear impact guards

* * * * *
    S5.1  Projected Vertical Height. The horizontal member of each 
guard, when viewed from the rear as it would be installed on a trailer 
pursuant to the installation instructions or procedures required by 
S5.5 of this standard, shall have a vertical height of at least 100 mm 
at each point across the guard width, when projected horizontally on a 
transverse vertical plane. Those installation instructions or 
procedures shall specify that the guard is to be mounted so that all 
portions of the horizontal member necessary to achieve a 100 mm high 
projected vertical height are located not more than 305 mm forward of 
the vehicle's rear extremity, as defined in S4 of 49 CFR 571.224, Rear 
Impact Protection. See Figure 1 of this section.
* * * * *
    S6.6  Force Application.
* * * * *
    (a) Using the force application device, apply force to the guard in 
a forward direction such that the displacement rate of the force 
application device is the rate, plus or minus 10 percent, designated by 
the guard manufacturer within the range of 2.0 cm per minute to 9.0 cm 
per minute. If the guard manufacturer does not designate a rate, any 
rate within that range may be chosen.
* * * * *
    3. In Sec. 571.224 section S3 is revised and section S4 is amended 
by adding a definition of pulpwood trailer and revising the definition 
of Special purpose vehicle to read as follows:


Sec. 571.224  Standard No. 224; rear impact protection

* * * * *
    S3. Application. This standard applies to trailers and semitrailers 
with a GVWR of 4,536 kg or more. The standard does not apply to pole 
trailers, pulpwood trailers, special purpose vehicles, wheels back 
vehicles, or temporary living quarters as defined in 49 CFR 529.2.
    If a cargo tank motor vehicle, as defined in 49 CFR 171.8, is 
certified to carry hazardous materials and has a rear bumper or rear 
end protection device conforming with 49 CFR part 178 located in the 
area of the horizontal member of the rear underride guard required by 
this standard, the guard need not comply with the energy absorption 
requirement (S5.2.2) of 49 CFR 571.223.
    S4. Definitions.
* * * * *
    Pulpwood trailer means a trailer that is designed exclusively for 
harvesting logs or pulpwood and constructed with a skeletal frame with 
no means for attachment of a solid bed, body, or container.
* * * * *
    Special purpose vehicle means a trailer or semitrailer having work-
performing equipment that, while the vehicle is in transit, resides in 
or moves through the area that could be occupied by the horizontal 
member of the rear underride guard, as defined by S5.1.1 through 
S5.1.3.
* * * * *
    Issued on: January 20, 1998.
Ricardo Martinez,
Administrator.
[FR Doc. 98-1783 Filed 1-21-98; 2:18 pm]
BILLING CODE 4910-59-P


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